for God's sake Take a plastic water pipe

Ris, let me know if you see anything that size.
I looked locally and online and couldn't find anything that size, any smaller or bigger than those dimensions and it's not going to work.

Russ, here's a drawing of what I need x2, as you can see it's just a short pipe cut in half

Quote from HMS-776 on January 7th, 2017, 01:47 PM

Thanks Russ, one thing,

Can you measure the capacitance of your coils and post them? Just curious to see if you'll get the same values.

I still think my coils should work, but tuning into resonance is more complex than just turning a knob.

I scanned 5-10kHz in 10Hz increments and saw no sign of resonance anywhere, yesterday?

If you think of the cell as a efficient capacitor then you can calculate the Q and bandwidth of the circuit, then finding resonance should be easy, if I remember right my VIC had a calculated bandwidth of 74Hz.

I think the water has to change in some way before resonance will show up, and that's the hard part?
So, in essence you could have the circuit at resonance and nothing will happen until the water does whatever it does before resonance appears.
I think I've probably hit and passed resonance multiple times but didn't notice because I didn't keep it on the frequency long enough?

There's got to be something more because finding resonance in a typical RLC circuit is easy.

I tried this once with a impedance measuring device…

You can only "know" the distributed self-capacitance and inductance of the (VIC) coils if you are using an impedance analyzer by calculating them from measuring VI (voltage, current) parameters: Frequency, Real, Imaginary , Impedance or Magnitude (SER or PAR). Just connecting an RLC meter won’t do it right, because it only using some fixed frequencies 100Hz, 120Hz, 1kHz, 10kHz or 100kHz etc. You need to find the peak (SRF).
 Then connecting the coils in series (opposing mode) will drop the inductance due the Mutual inductance. What you think will happen with the distributed self-capacitance? It changed too, right?

 So using a impedance meter with frequency sweep you can test the (VIC) DUT (device under test). You need to look for a first peak (SRF) where the voltage will be the highest on both chokes equal but opposite voltage outputs (B+ and B-) and here is the SRF frequency. Then also changing voltage amplitude to drive the circuit changes the inductance of the coils (core material) and you end up with different values but I think it is a scaling factor of the SRF. Not sure…

~webmug
 

What k parameter do you guys use for calculating the mutual inductance?

~webmug

Webmug, Brad, and Ronnie

I have been deeply thinking about SRF, & How it can be directly applied to the known "what to do's"

so the first thing i want to do is that, measure all the SRF and resistances and try to determine if there is something useful there.

Ronnie, do you have anything to say about this path?

Webmug, using the same device you used i will be checking for SRF. would you mined posting any information on your experience even more than you already did? i think it would be helpful. also i dont have the device name here with me and forgot to post it. if you can that be great, if not ill get mine when i get home.

Brad, what have you been thinking as of the SRF and tuning / math? can you go deeper in to your thought process?

thanks!! hope to get some more data soon on SRF of the coils i made.

~Russ

Quote from ~Russ on January 11th, 2017, 01:17 PM

Webmug, Brad, and Ronnie

I have been deeply thinking about SRF, & How it can be directly applied to the known "what to do's"

so the first thing i want to do is that, measure all the SRF and resistances and try to determine if there is something useful there.

Ronnie, do you have anything to say about this path?

Webmug, using the same device you used i will be checking for SRF. would you mined posting any information on your experience even more than you already did? i think it would be helpful. also i dont have the device name here with me and forgot to post it. if you can that be great, if not ill get mine when i get home.

Brad, what have you been thinking as of the SRF and tuning / math? can you go deeper in to your thought process?

thanks!! hope to get some more data soon on SRF of the coils i made.

~Russ

Using that EVAL-AD5933EBZ Rev. C pcb, has some issues that I never solved. You need to use a calculated Rfb (feedback resistor) on the input opamp stage for a impedance you want to measure. So that Min,Max, impedance is the range of your DUT. The calculations are in the datasheet. So some Rfb switching is needed for the DUT you want to test. Then you need to calculate the parameters, C, L etc. from the Re and Img etc.

http://www.farnell.com/product360s/images/EVAL-AD5933EBZ/EVAL-AD5933EBZ-big-01.jpg
http://www.analog.com/media/en/technical-documentation/evaluation-documentation/537700023EVAL_AD5933EB.pdf
 http://www.analog.com/media/en/technical-documentation/application-notes/AN-1252.pdf

For some arduino hacking use:
http://store.digilentinc.com/pmod-ia-impedance-analyzer/

~webmug

Boy, some good stuff there Webmug.

Here's one little snippet to think about.

Webmug Self-resonant frequency can be measured with impedance analyzer that is the best and accurate approach, but it can be done by "pinging" the coil with a short pulse with a diode and freq. generator and watch the "ring" on the scope of its self-resonant frequency across the inductor. This is not the most accurate approach but can show the aproximate value, since the real inductor has the characteristics of an RLC circuit.

Russ & Webmug,

Webmug you are correct. You can't get accurate measurements using an RLC meter. But I was not looking for exact measurements, just trying to rule out the source of resonance I was getting between 20-30kHz.

I did that using 3 different methods.
1. The ring test
2. Test with signal gen, oscope, and a current pickup coil (current sense transformer) looking for peak currents.
3. Physical measurements

All three tests showed that what I was seeing was indeed the SRF of the choke coils. This led me to find out that at one point I accidentally swapped my chokes so that they were opposing each other.

As far as the SRF goes I don't think it has a role in how the VIC operates, I think the coil capacitance plays an important role though.

There is another coil resonance that could be occurring which happens when the coils capacitance couples with a nearby object and forms a series resonant circuit.

Personally I think the VIC resonance occurs like Stan says, between the L1 choke and the cell. But it appears that more has to happen for the circuit to see the cell as a capacitor. Like I mentioned before as you scan through the frequency range you see a multitude of peaks on the fft. Many of the peaks are about the same amplitude and no clearly defined resonant peaks appear. There's got to be something occurring in the cell that causes it to become a real capacitance....otherwise all your doing is putting square waves into a non linear resistance, that's why you'll see a multitude of peaks but no clearly defined resonant point. What your seeing are smaller oscillations of the square waves being broken up into an infinite number of sine waves (Fourier series ).....the resistances in the cell match to some of those frequencies  and show up on the scope.

My scope only goes to 40MHz. The circuit operates in the audio range 1-20kHz, but when testing I have measured frequencies above 10MHz at very low amplitudes.

imagine if your oscope was creating loading effects, preventing you from hitting resonance.... mabye you should look at the bubbles, and disconnect your scope

He should be running the cell dry at this point.  If there is water in there, he'll have a whole other set of problems to deal with before there is any resonance.

I do tend to agree about connecting instrumentation to a device which actually prevents the device from operating correctly though.  I've seen that happen many times before.  I've also seen the reverse where the DUT only works when connected to scopes and such.

i dont know why he would be running it dry... tap water creates a dead short.....

with just air its essentially just an open circuit with like no capacitive effects....

water shouldent present capacitive effects either, but alas stan says it does so we have no choice to belive him right?....

Belief on its face is not peer review.

Reverendkilljoy,

My scope is not directly connected to the circuit, it's coupled to a single wire going into the primary coil so the coupling is very small, at worst it would effect the vic much less than the pickup coil Stan used on his vic.

I am testing the cell with rain water in it, I tried distilled with no results.

HMS
Stan have test point to see the resonance on the output of pulser indicator circuit - test jack on the figure 9.

Alright. After some days of printing new stand off holders for the Vic. I put the farite cores in the Vic. I use one thickness of clear scotch tape as a separator. I think these cores need a gap according to the high inductance values I get when there closed.

Cells are still dry.

Mesuring the L1 and L2 coils with a refrance ground as the stright conection between the L2 and Sec

Probes are 2.5pf and 40Mohms so they must be factored in

I was able to get resonance between thses points at different frequnces.

Max voltages I was seeing was around 165vPk-Pk

What was interesting was that I was able to get a really nice doubling effect at a set F

But also get both coils resonating at a different F

Also, let's be clear here. Using stans circuit for driving at around 5v. Anything past around 10khz the pulse with across the primary is no where near 50% in fact to get 50% duity across primary the coil at 20khz required 99% duity cycle input ( 1% Not inverted)

Kind interesting.

~Russ

I will add the live stream once it's processed.

Oh and somthinh to add. I was only able to see the doubling on the L1 coil. This makes sentce according to what I know about where the dioed is placed. 

Quote from ~Russ on January 11th, 2017, 10:33 PM

Oh and somthinh to add. I was only able to see the doubling on the L1 coil. This makes sentce according to what I know about where the dioed is placed.

It also makes sense because L1 is on the other core half away from the primary.

So let me ask, are you seeing any frequency doubling on the secondary?

Quote from ~Russ on January 11th, 2017, 10:26 PM

Max voltages I was seeing was around 165vPk-Pk

You won't be jumping any sparks with that voltage but the frequency range of around 12kHz is encouraging.

Matt. I'll need to measure the sec.

Yeah. Nothing is tuned here eather. Lots of things to adjust.

I just wanted to see what happens "out of the box"

~russ

Ok. Quick before work day testing. Added the sec mesurememt.

So that's now blue.

You can kinda get the sec to double. But not really.

However. At low frequncys there is the quite large peek on the primary. Mesuring across it. Its not ringing due to the dioeds. But it is spiking. Allmoat 2x the input.

Here are a lot of photos for your viewing pleasure.

Rember gnd refrance point is between the sec and L2

Yellow is L2
Purple is L1
Blue is Sec
Green is primary

I mesured each ring with the cursers.
~Russ

Ring test.

This is a rather intresting thing. You can see each coil ringing high or low. But the L2 is allways in the middle.

Here is trying to find doubling on the SEC

The voltages are so low it's kinda usless.

Also note that changing voltage really changes the behavior of this completely.


Also note that the sec is out of phase from L2 and L1

~Russ

Quote from HMS-776 on January 10th, 2017, 03:58 PM

Ris, let me know if you see anything that size.
I looked locally and online and couldn't find anything that size, any smaller or bigger than those dimensions and it's not going to work.

Russ, here's a drawing of what I need x2, as you can see it's just a short pipe cut in half

http://www.vodoskok.hr/prodajni-program/sustavi-opskrbe-prirodnim-plinom/cijevi-za-opskrbu-prirodnim-plinom/
exact inner diameter   outside diameter is slightly larger ie twice thicker than your specifications  it should not be a problem By the way  you have room for cover mounting  that is another plus
This company is in my country but the it does not matter plastic gas pipes should be the same all over the world
so find an acquaintance someone who works on construction field  If you ask nicely they'll  surely give you a piece of pipe

Quote from ~Russ on January 12th, 2017, 08:24 AM

Yellow is L2
Purple is L1
Blue is Sec
Green is primary

More good hard data Russ.  Awesome work!

Here's an annotated schematic for the ping test to study.  Hope I have the data points correct.

Just looking at this from a distance with an untrained eye, it would appear you have the greatest number of windings on the L2, less on L1 and the fewest on the secondary.  I'm sure that's not the case, but I'm curious as to why the numbers come out like that.  It has to be the interwinding capacitance responsible for the these ring points.  Each coil seems to be its own tank circuit.